Variations on a segmental theme: muscle receptor organs and extensor neuromusculature in the squat lobster Munida quadrispina (Anomura, Galatheidae)

1995 ◽  
Vol 198 (12) ◽  
pp. 2453-2463 ◽  
Author(s):  
E Wallis ◽  
D Paul ◽  
B Antonsen ◽  
R Hollenberg
Keyword(s):  
Relative Size ◽  
Extracellular Recording ◽  
Blue Staining ◽  
Squat Lobster ◽  
Muscle Receptor ◽  
Axial Muscles ◽  
Extensor Motoneurones ◽  
The Difference ◽  
Segmental Variation ◽  
Species Specific

Extensor neuromusculature and the muscle receptor organs (MROs) associated with them have been conserved during the evolution of malacostracan crustaceans, despite species-specific differences between homologous segments in divergent taxa. Investigations of these differences could provide insight into how sensory and neuromuscular elements are modified to accommodate changing behavioural patterns. The most obvious differences between squat lobsters (galatheid anomurans) and macruran decapods, such as crayfish, are the greater dorso-ventral flattening of the galatheid abdomen and its flexed resting posture. To investigate whether the evolution of this altered posture affected extensor neuromusculature and MRO morphology and physiology, we used Methylene Blue staining, cobalt backfilling and extracellular recording techniques to describe these elements in the caudal thoracic and six abdominal segments of the squat lobster Munida quadrispina and compared our results with published descriptions of homologous elements in macrurans. In M. quadrispina, there is segmental variation both in the orientation of the MROs along the abdomen and in their physiological responses to stretch: apparent sensitivity is higher in caudal than rostral MROs. Homologues of three of the four accessory neurones found in crayfish occur, but AN#1 has a major dendrite not present in crayfish. Intersegmental differences in size and morphology of extensor motoneurones occur in M. quadrispina, as have been reported in crayfish, but are dissimilar in the two: abdominal ganglion 5 extensor motoneurones are the largest in M. quadrispina and the smallest in crayfish; this difference correlates with the difference in relative size of axial muscles along the abdomen reported previously for these species. M. quadrispina also differs from macrurans in having a single tonic, and no phasic, MRO on each side of the last abdominal segment. Together, these observations suggest that galatheids have evolved modified or additional neurobehavioural control(s) for the abdomen and tailfan.

scholarly journals SOST Deficiency Aggravates Osteoarthritis in Mice by Promoting Sclerosis of Subchondral Bone

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Jingyu Li ◽  
Junjie Xue ◽  
Yan Jing ◽  
Manyi Wang ◽  
Rui Shu ◽  
...  
Keyword(s):  
Subchondral Bone ◽  
Cruciate Ligament ◽  
Cartilage Degradation ◽  
Cell Number ◽  
Blue Staining ◽  
Sham Operation ◽  
Knee Oa ◽  
Sost Gene ◽  
Bone Sclerosis ◽  
The Difference

As the initial part in the development of osteoarthritis (OA), subchondral bone sclerosis has been considered to be initiated by excess mechanical loading and proven to be correlated to other pathological changes. Sclerostin, which is an essential mechanical stress response protein, is encoded by the SOST gene. It is expressed in osteocytes and mature chondrocytes and has been proven to be closely correlated to OA. However, the relationship and mechanism between the SOST gene and the development of OA remain unclear. The aim of the present study was to investigate the role of the SOST gene in OA pathogenesis in the subchondral bone. A knee anterior cruciate ligament transection (ACLT) mouse osteoarthritis (OA) model on SOST-knockout (SOST KO) and wild-type (WT) mice was established. The pathogenic and phenotypic changes in the subchondral bone were investigated by histology, micro-CT, immunohistochemistry, TRAP staining, Masson staining, and Toluidine blue staining. It was found that sclerostin expression decreased in both the calcified cartilage and mineralized subchondral structures during the development of OA. Joint instability induced a severe cartilage degradation phenotype, with higher OARSI scores in SOST KO mice, when compared to WT mice. SOST KO mice with OA exhibited a higher BMD and BV/TV ratio, as well as a higher rate of bone remodeling and TRAP-positive cell number, when compared to the WT counterparts, but the difference was not significant between the sham-operation groups. It was concluded that loss of sclerostin aggravates knee OA in mice by promoting subchondral bone sclerosis and increasing catabolic activity of cartilage.

Size Selectivity of Diamond and Square Mesh Codends in Pelagic Herring Trawls: Only Small Herring Will Notice the Difference

1992 ◽  
Vol 49 (10) ◽  
pp. 2104-2117 ◽  
Author(s):  
Petri Suuronen ◽  
Russell B. Millar
Keyword(s):  
Relative Size ◽  
Mesh Size ◽  
The Other ◽  
Size Selectivity ◽  
The Difference ◽  
Catch Rates ◽  
Two Sides ◽  
High Catch

A twin codend trawl was fished in the northern Baltic to study the size selectivity of square mesh and diamond mesh codends of 36-mm nominal mesh size. For each codend, 15 hauls were completed with a small mesh (20 mm) codend deployed on the other side of the trawl. The relative size of the catches in the two sides of the trawl varied considerably from haul to haul (the separator section was not operating properly) and selection curves were estimated from each individual haul using a method that incorporated the differences in catching efficiency of the two sides. The length of 50% retention decreased with increased catch for both the diamond and square mesh codends, although in neither case was this relationship statistically significant. Selection curves fitted to the combined haul data were asymmetric. The square mesh codend retained significantly less small herring than the diamond mesh codend, and for larger herring the two codends had similar selectivity. In both codends, most escapes occurred at the front of the catch bulge, from the upper side of the codend. At high catch rates, mesh blockage was observed for several metres ahead of the catch bulge during the later part of the tow.

scholarly journals The megalopa stage of Portunus spinimanus Latreille, 1819 and Portunus gibbesii (Stimpson, 1859) (Decapoda, Brachyura, Portunidae) from the southeastern Atlantic coast of the United States

Zootaxa ◽  
2007 ◽  
Vol 1638 (1) ◽  
pp. 21-37 ◽  
Author(s):  
MARIA LUCIA NEGREIROS-FRANSOZO ◽  
NADIA MEYERS ◽  
VÍVIAN FRANSOZO ◽  
SUSAN THORTON-DE VICTOR
Keyword(s):  
South Carolina ◽  
Atlantic Coast ◽  
Relative Size ◽  
The United States ◽  
Species Level ◽  
Crab Larvae ◽  
Juvenile Instar ◽  
Species Specific ◽  
Swimming Crabs ◽  
Southeastern Atlantic

The identification of megalopae from plankton samples is difficult, because this larval stage is the least well known among crab larvae, unknown in some species and poorly described in others. Wild megalopa specimens of some swimming crabs (family Portunidae Rafinesque, 1815) were captured alive from neuston samples obtained during summer surveys near the coast of Charleston, South Carolina (U.S.A). For identification purposes, larvae were reared to the 8th juvenile instar. After reaching the 5th juvenile instar, the juvenile crabs exhibited morphological features suitable for identification to the species level. The specimens belonged to two species of Portunidae, Portunus spinimanus Latreille, 1819 and P. gibbesii (Stimpson, 1859). Their megalopae were described in detail and compared to other portunid megalopae known from the southeastern Atlantic coast of the U.S.A. Species-specific characters of portunid megalopae are the number of carpal spines on the chelipeds, the relative size of the sternal spines (7th sternite), the number of antennal flagellum segments, and the setation of mouthparts.

scholarly journals Ba incorporation in benthic foraminifera

2017 ◽  
Author(s):  
Lennart J. de Nooijer ◽  
Anieke Brombacher ◽  
Antje Mewes ◽  
Gerald Langer ◽  
Gernot Nehrke ◽  
...  
Keyword(s):  
Trace Elements ◽  
Benthic Foraminifera ◽  
General Trend ◽  
Seawater Chemistry ◽  
Minor And Trace Elements ◽  
Foraminiferal Species ◽  
Element Partitioning ◽  
The Difference ◽  
Species Specific ◽  
New Applications

Abstract. Barium (Ba) incorporated in the calcite of many foraminiferal species is proportional to the concentration of Ba in seawater. Since the open ocean concentration of Ba closely follows seawater alkalinity, foraminiferal Ba/Ca can be used to reconstruct the latter. Alternatively, Ba/Ca from foraminiferal shells can also be used to reconstruct salinity in coastal settings where seawater Ba concentration corresponds to salinity as rivers contain much more Ba than seawater. Incorporation of a number of minor and trace elements is known to vary (greatly) between foraminiferal species and application of element/Ca ratios thus requires the use of species-specific calibrations. Here we show that calcite Ba/Ca correlates positively and linearly with seawater Ba/Ca in cultured specimens of two species of benthic foraminifera, Heterostegina depressa and Amphistegina lessonii. The slopes of the regression, however, vary 2–3 fold between these two species (0.33 and 0.78, respectively). This difference in Ba-partitioning resembles the difference in partitioning of other elements (Mg, Sr, B, Li and Na) in these foraminiferal taxa. A general trend across element partitioning for different species is described, which may help developing new applications of trace elements in foraminiferal calcite in reconstructing past seawater chemistry.

Influence of Freshwater Migration on the Reproductive Patterns of Anadromous Populations of Cisco (Coregonus artedii) and Lake Whitefish (C. clupeaformis)

1990 ◽  
Vol 47 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Yvan Lambert ◽  
Julian J. Dodson
Keyword(s):  
Adult Mortality ◽  
Lake Whitefish ◽  
Age At Maturity ◽  
Predominant Role ◽  
Reproductive Patterns ◽  
Interspecific Differences ◽  
Survival And Reproduction ◽  
Coregonus Artedii ◽  
The Difference ◽  
Species Specific

We tested the hypothesis that differences in the cost of freshwater migration are responsible for the different reproductive patterns exhibited by the Eastmain River (James Bay) populations of anadromous cisco and lake whitefish, as predicted by species-specific migration costs that result in interspecific differences in energy allocation to growth, survival, and reproduction. In the Eastmain River, cisco spawn at a younger age and a smaller size, have a shorter life span and show a higher fecundity and a higher mortality than lake whitefish. Assuming that the two populations are stable (being only lightly exploited), the two species spawn at an age that maximizes their lifetime fecundity. Either juvenile (between three and age at maturity) and/or adult mortality is of major importance in moulding the observed age at maturity but adult mortality may play a predominant role. Adult mortality is associated with migration, an obligatory cost representing a major proportion of the energy loss experienced by reproductive individuals. The difference in the energy cost of migration between the two species suggests that migration may play a predominant role in producing the different reproductive patterns of cisco and lake whitefish in the Eastmain River and that within the physiological and size constraints of each species, these patterns represent optimal adaptations maximizing fitness.

scholarly journals The tax gap as a public management instrument: application to wealth taxes

2019 ◽  
Vol 27 (81) ◽  
pp. 207-225
Author(s):  
José M. Durán-Cabré ◽  
Alejandro Esteller Moré ◽  
Mariona Mas-Montserrat ◽  
Luca Salvadori
Keyword(s):  
Public Management ◽  
Design Methodology ◽  
Relative Size ◽  
Tax Compliance ◽  
Content Type ◽  
Tax Gap ◽  
Wealth Tax ◽  
The Difference ◽  
Gift Tax ◽  
Over Time

Purpose The purpose of this paper is to study the concept of tax gap, that is the difference between the total amount of taxes collected and the total tax revenues that would be collected under full tax compliance. Design/methodology/approach The authors also present the methodology to estimate the gap for two taxes levied on wealth: the wealth tax and the inheritance and gift tax; both are administered in Spain by the regional tax authorities. Findings The authors point out that its estimation offers useful information about the relative size and nature of non-compliance, as well as its evolution over time. Likewise, the tax gap is a valuable instrument not only to define enforcement strategies of the tax administration but also to enhance its accountability. Nonetheless, the methodology used to estimate the tax gap and, consequently, the interpretation of the results is subject to limitations that are discussed in the paper. Originality/value Finally, the paper provides the results of the estimations obtained from using microdata: 44.34 per cent gap in the wealth tax and 41.26 per cent in the inheritance and gift tax.

BIOSYSTEMATICS OF THE GENUS EUXOA (LEPIDOPTERA: NOCTUIDAE). XVIH. COMPARATIVE BIOLOGY AND EXPERIMENTAL TAXONOMY OF THE SIBLING SPECIES EUXOA RIDMGSIANA (GRT.) AND EUXOA MAIMES (SM.)

1985 ◽  
Vol 117 (4) ◽  
pp. 481-493 ◽  
Author(s):  
J.R. Byers ◽  
D.L. Struble ◽  
J.D. Lafontaine
Keyword(s):  
Life Cycle ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Mate Recognition ◽  
Recognition System ◽  
Flight Period ◽  
Interspecific Differences ◽  
Mate Recognition System ◽  
The Difference ◽  
Species Specific

AbstractThe species previously recognized as Euxoa ridingsiana (Grt.) is shown to be composed of a sympatric pair of sibling species, Euxoa ridingsiana (Grt.) and Euxoa maimes (Sm.), which in the laboratory will produce viable F1 hybrids but no F2. Results of F1 sib and backcrosses show that the F1 males are fertile and the F1 females are infertile. In mating-bias tests conducted in laboratory cages, 74% of matings were conspecific and 26% interspecific. Differences in the diel periodicities of mating, which are about 2 h out of phase, may account for the mating bias. The duration of development of E. ridingsiana in the laboratory and its seasonal flight period in the field are about 2 weeks in advance of that of E. maimes. However, there is considerable overlap of the flight periods and, with the tendency of females of both species to mate several times, it is unlikely that the difference in seasonal emergence is enough to effect reproductive isolation. It is evident that, under natural conditions, reproductive isolation can be maintained entirely by species-specific sex pheromones. This mechanism of reproductive isolation is, however, apparently ineffective when moths are confined in cages in the laboratory.Biogeographic considerations suggest that the differences in life-cycle timing and mating periodicities might have been adaptations to adjust development and reproduction to prevailing ancestral environments. If the initial differentiation of the 2 species occurred in isolation and included at least an incipient shift in the pheromonal mate-recognition system, it is possible that upon reestablishment of contact between ancestral populations the differences in life-cycle timing and mating periodicities acting in concert could have effected substantial, albeit incomplete, reproductive isolation. Subsequent selection to reinforce assortative mating to preserve coadapted gene complexes could then have resulted in differentiation of discrete pheromonal systems and attainment of species status.

METHYL ACTIVATION AND sRNA METHYLATION BY SOLUBLE FRACTIONS OF SEVERAL VERTEBRATE LIVERS

1967 ◽  
Vol 45 (10) ◽  
pp. 1513-1522 ◽  
Author(s):  
R. L. Hancock
Keyword(s):  
Mouse Liver ◽  
Specific Interaction ◽  
Adult Rabbit ◽  
X Chromosomes ◽  
E Coli ◽  
Lower Vertebrates ◽  
The Difference ◽  
Species Specific ◽  
Methylase Activity

The amount of liver ATP: L-methionine S-adenosyltransferase activity varies widely in vertebrates from trace amounts in certain lower vertebrates, e.g. shark or turtle, to relatively large quantities in mammals, e.g. mouse or rabbit. The liver from male mice of a particular stock had only two-thirds the activity of female mouse liver. This difference is not explained by the difference between the sexes in number of X-chromosomes, since female mice with only one X-chromosome (X/0) had the same levels of liver S-adenosyltransferase activity as normal females with two X-chromosomes.sRNA methylase activity from mouse, shark, and rabbit liver supernatant fractions were studied with mouse, shark, and Escherichia coli sRNA. Highspeed supernatant fractions from both rabbit embryonic liver and mouse hepatoma hypermethylated E. coli sRNA which had been previously methylated by adult rabbit or mouse liver supernatant fractions. Hepatoma methylase(s) acts in an analogous manner to that of a species-specific interaction with heterologous and homologous sRNA.A calculation is made comparing the amount of sRNA methylase activity detected in vitro with mouse liver sRNA, with one which is theoretically derived; similar values are obtained. The variation found in vertebrate liver with respect to methyl activation and sRNA methylation is discussed.

scholarly journals Anatomical Study of Caudal Vertebrae of Estuary Crocodile (Crocodylus porosus), Chameleon (Bronchocela jubata) and Klarap (Draco volans)

2019 ◽  
Vol 2 ◽  
pp. 3-7
Author(s):  
Aidha Rosel ◽  
Safitri Anggita Tunjung Sari ◽  
Umi Uswatun Hasanah
Keyword(s):  
Bone Structure ◽  
Anatomical Study ◽  
Anatomical Structure ◽  
Morphological Observation ◽  
Blue Staining ◽  
Alcian Blue Staining ◽  
Ray Method ◽  
Caudal Vertebrae ◽  
Crocodylus Porosus ◽  
The Difference

Reptile tails have a unique function as self defense, autotomy, and maintaining balance while in nature. There are several species that do not have an autotomy function, these species include Estuary Crocodile (Crocodylus porosus), Java Chameleon (Bronchocela jubata), and Klarap (Draco volans). The species is a reptile class that uses its tail with different functions. Differences in function in the tail can be caused by differences in anatomical structure, morphology, and behavioral adaptations that are owned by each species. With the differences in each species, this study aims to get a comparative picture of the caudal vertebrae (coccyx) anatomy of species of estuary crocodile (Crocodylus porosus), java chameleon (Bronchocela jubata), and klarap (Draco volans) so that anatomical comparison can be seen in each species that affects the difference in tail function. The method used in this study is morphological observation with boiled method, X-Ray method, and Alizarin Red's and Alcian Blue staining methods. Research that has been conducted shows that the anatomical structure of caudal vertebrae (coccyx) in estuary crocodile species has a larger bone structure than the bone structure of java chameleon and klarap. The anatomical structure of caudal vertebrae (coccyx) in klarap has a smaller bone structure than estuary crocodile and java chameleon. The anatomical structure of caudal vertebrae (coccyx) in java chameleon species has a longer bone structure than its body length. Caudal vertebrae of these three species do not have tail fracture fields.

scholarly journals Single-stage prediction models do not explain the magnitude of syntactic disambiguation difficulty

2020 ◽  
Author(s):  
Marten van Schijndel ◽  
Tal Linzen
Keyword(s):  
Neural Network ◽  
Prediction Models ◽  
Relative Size ◽  
Language Models ◽  
Ambiguous Sentence ◽  
Linear Effect ◽  
Garden Path ◽  
Recovery Mechanisms ◽  
The Difference ◽  
Network Language

The disambiguation of a syntactically ambiguous sentence in favor of dispreferred parse can lead to slower reading at the disambiguation point. This phenomenon, referred to as a garden path effect, has motivated models in which readers only maintain a subset of the possible parses of the sentence; reverting to a discarded parse requires costly reanalysis. More recently, it has been proposed that the garden path effect can be reduced to surprisal arising in a fully parallel parser: words consistent with the initially dispreferred but ultimately correct parse are simply less predictable than those consistent with the incorrect parse. The surprisal account is more parsimonious since predictability has pervasive effects in reading far beyond garden path sentences. Crucially, this account predicts a linear effect of surprisal: the difficulty experienced by readers should be proportional to the difference in word surprisal between the ultimately correct and ultimately incorrect interpretations. To test this prediction, we estimated word-by-word surprisal using recurrent neural network language models, comparing those estimates to self-paced reading times for three garden path constructions. While surprisal successfully predicted the existence of garden path responses, it severely underpredicted the magnitude of all of the garden path effects. Further, the relative size of the predicted effects was inconsistent with the relative size of the responses in humans, indicating that a differently scaled linking function would not be able to predict the response magnitudes either. These results support two-stage processing models in which recovery mechanisms beyond predictability are involved in processing garden path sentences.

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